Hills x/d discontinued. Best Diet for oxylate crystals? in my cat?

Question
Thanks for your time and concern. The altered male cat I have adopted  has
had oxylate crystals and stones removed from his bladder. He has been on a
Hills Prescription c/d dry food diet for a year in a foster care situation. He
had a urine Ph of 6.5 on this diet and no symptoms.
My own vet wants to transfer him to a Hills Prescription x/d diet. On line
research reveals that this diet food has been discontinued by Hills and
replaced by the c/d diet.  It was my understanding that the c/d diet  was not
well suited  for cats with calcium  oxylate crystals but intended for another
type of urinary crystals.  Will feeding Hills c/d harm my cat?

Thanks for your help
RACHEL

Answer
Rachel -

Hill's c/d will be good for your cat.  The diet is designed to inhibit the growth of certain crystals. For a more indepth discussion of the different types of diets, call the number on the back of the Hill's cat food bag. Customer service will be happy to discuss different diets with you.

Charlotte Sherrell, DVM